Cryptology ePrint Archive: Report 2010/637

Breaking An Identity-Based Encryption Scheme based on DHIES

Martin R. Albrecht and Kenneth G. Paterson

Abstract: We present collusion attacks against a recently proposed IBE scheme of Chen et al. from ASIACCS 2010. The attacks recover the master secret key of the scheme and thereby invalidate the existing security analysis of this scheme. The attacks are flexible, allowing, for example, the amount of computation needed to be traded-off against the size of the collusion.